JPH04272553A - Friction continuously variable transmission - Google Patents

Abstract

PURPOSE:To miniaturize and lighten a friction continuously variable transmission by integrating a reduction mechanism which corresponds to a primary reduction gear and the continuously variable transmission together, and allocating transmission power to a speed reducer and a speed change gear. CONSTITUTION:When torque is transmitted to the input shaft 8 of a friction continuously variable transmission 2, the torque is transmitted to an epicyclic gear 18 by a sun gear 16 provided on the outer periphery of the output side end portion of the input shaft 8 and half of the torque is transmitted to an output shaft 10 via the carrier 18a of the epicyclic gear 18. The other half of the torque is transmitted to a small diameter transmission car 22 from the epicyclic gear 18 via an inner toothed gear 20 and is transmitted from the small diameter transmission car 22 to a large diameter transmission wheel 34 via a conical rolling element 28. Torque from the large diameter transmission wheel 34 is transmitted to the output shaft 10 via thrust cams 36a, 36b, a thrust ball 38, and a thrust cam return spring 40. Torque is thus made to diverge and so large torque can be transmitted even in a continuously variable transmission with a small capacity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable friction transmission suitable for use in various types of work vehicles.

0002

[Prior Art] In general, a work vehicle has a transmission system that includes a reduction mechanism that primarily reduces the rotational speed of the engine, a continuously variable transmission that enables traveling speed change, and a gear reduction gear that obtains output torque. The system uses a system in which the power is transmitted to the rear wheels via the axle. In addition, as the above-mentioned continuously variable transmission, it is possible to continuously obtain the desired rotation speed from stop (zero rotation) to the desired rotation speed.
The friction continuously variable transmission described in Japanese Patent No. 13221 is used.

0003

[Problems to be Solved by the Invention] In the above work vehicle, the engine, the reduction mechanism for primary reduction, the mechanical continuously variable transmission, and the final gear reduction gear are arranged in series, so the space for the transmission system is limited. It is largely occupied.

[0004] Therefore, it is difficult to downsize the vehicle due to space constraints, and all the transmitted power is directly received from the engine to the final reduction gear.

In order to solve the above-mentioned problems, the present invention integrates a reduction mechanism corresponding to primary reduction with a continuously variable transmission, and shares the transmitted power between the reduction gear and the transmission. The purpose of the present invention is to provide a friction continuously variable transmission suitable for work vehicles that require reduction in size and weight.

[0006]

[Means for Solving the Problems] The present invention provides a conical surface that is inscribed in and frictionally engaged with a speed change ring that is kept in a non-rotating state, and an annular surface that is frictionally engaged with a small diameter transmission wheel on an input shaft. A plurality of conical rotors are provided on the transmission system, each having a flat transmission surface that is frictionally engaged with the large-diameter transmission wheel, and the rotation of the large-diameter transmission wheel generates a cam-type pressure contact force. A sun gear on the input shaft; A differential gear device includes an internal gear that is rotated integrally with a small-diameter transmission, a planetary gear interposed between the internal gear and the sun gear, and a carrier for the planetary gear. , characterized in that one end of the output shaft is engaged with the carrier of the differential gear device.

[0007]

[Operation] With the above configuration, when rotational force is transmitted to the input shaft of the friction continuously variable transmission, the rotational force from the input shaft is transmitted to the differential gear mechanism, and this differential gear mechanism One side of the rotational force is transmitted to the output shaft, and the other side of the rotational force is transmitted to the output shaft via the continuously variable transmission mechanism, dividing the rotational force and producing large torque with a small capacity continuously variable transmission. The input shaft of the continuously variable transmission can be rotated at high speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. In FIG. 2, 2 is a friction continuously variable transmission.

As shown in FIGS. 1 and 2, this friction continuously variable transmission 2 has a planetary differential gear mechanism 4 and a continuously variable transmission mechanism 6, and the combination of these mechanisms 4 and 6 allows forward rotation. , any gear ratio can be operated steplessly over the entire stopping range.

That is, the friction continuously variable transmission 2 is provided with an input shaft 8 and an output shaft 10 having the same central axis,
The differential gear mechanism 4 is provided on the outer periphery of the input shaft 8, and the continuously variable transmission mechanism 6 is provided on the outer periphery of the output shaft 10.

In detail, the input shaft 8 and the output shaft 10
A case 14 is provided on the outer periphery of the input shaft 8 via radial bearings 12-1 and 12-2, and within this case 14, a plurality of planetary gears 18 are provided on the outer periphery of the output side end of the input shaft 8 via a sun gear 16. A small diameter transmission wheel 22 of the continuously variable transmission mechanism 6 is connected to the planetary gear 18 via an internal gear 20.
is integrated into. At this time, the carrier 18a of the planetary gear 18 is engaged with one end of the output shaft 10.

Furthermore, a cone retainer 30 is provided which frictionally engages the annular surface 28a of a plurality of conical rotors 28, for example, three or five conical rotors 28, on the outer periphery of the small-diameter transmission wheel 22, and pivotally supports the conical rotors 28. and a conical trochanter 28
A speed change ring 32, which is a circular frame member, is provided to be inscribed on the outer periphery of the frame. One of the generatrices of the cone of the conical trochanter 28 is arranged approximately parallel to the input shaft 8, and each conical trochanter 2
8 are arranged at equal intervals around the circumference of the input shaft 8.

A large diameter transmission wheel 34 is provided in contact with a substantially flat surface 28b provided on the back side of the conical surface of the conical rotor 28, and this large diameter transmission wheel 34 is connected to the thrust cams 36a, 36.
b. A cam pressure generating device consisting of a thrust ball 38 and a thrust cam return spring 40 is connected to the output shaft 1.
0. Provided on the outer periphery.

An oil seal 42 is provided between the input/output shafts 8, 10 and the case 14.

Furthermore, the input end of the output shaft 10 is pivotally attached to the inner periphery of the input shaft 8 via a needle bearing 46.

Then, the differential gear mechanism 4 is connected to the sun gear 1.
6, a planetary gear 18, and an internal gear 20, the continuously variable transmission mechanism 6 is composed of a small diameter transmission wheel 22 and a conical rotor 2.
8, a cone retainer 30, a speed change ring 32, and a large diameter transmission wheel 34.

Furthermore, the speed change ring 3 of the continuously variable transmission mechanism 6
A mechanism (not shown) is provided to support the input shaft 2 so as to be slidable in the axial direction of the input shaft 8 and to restrict the rotational direction.

The cam-type pressing force generating device has a function of applying a pressing force approximately proportional to the load torque on the output shaft to the contact portion of the conical rotor 28, thereby ensuring torque transmission.

Next, the operation will be explained.

When the rotational force is transmitted to the input shaft 8 of the friction continuously variable transmission 2, the rotational force from the input shaft 8 is transmitted to the differential gear mechanism 4. One of the rotational forces is transmitted to the output shaft 10, and the other rotational force is transmitted to the output shaft 10 via the continuously variable transmission mechanism 6.

That is, the rotational force transmitted to the input shaft 8 is transmitted to the planetary gear 18 by the sun gear 16 provided on the outer periphery of the output side end of the input shaft 8, and one side of the rotational force is transmitted to the carrier of the planetary gear 18. It is transmitted to the output shaft 10 via 18a.

The other rotational force is transmitted from the planetary gear 18 to the small diameter transmission wheel 22 via the internal gear 20, and from this small diameter transmission wheel 22 to the large diameter transmission wheel 34 via the conical rotor 28. communicated. The rotational force from the large diameter transmission wheel 34 is transmitted to the thrust cams 36a, 36b and the thrust balls 3.
8. The thrust cam is transmitted to the output shaft 10 via the respective thrust cam return springs 40.

With this, when rotational force is transmitted to the input shaft 8 of the friction continuously variable transmission 2, one side of the rotational force is transmitted to the output shaft 10 via the differential gear mechanism 4, and the rotational force is transmitted to the output shaft 10 via the differential gear mechanism 4. The other one is transmitted to the output shaft via the differential gear mechanism 4 and the continuously variable transmission mechanism 6, respectively, and the rotational force is divided, so that a large torque can be transmitted with a small capacity continuously variable transmission.

Furthermore, by reducing the input rotational speed to the continuously variable transmission mechanism 6 by the differential gear mechanism 4 in the preceding stage, the input shaft 8 can be rotated at a high speed.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

For example, in the embodiments of the present invention, a frictionally continuously variable transmission is described, but any device having a frictionally continuously variable transmission function may be used, such as a belt type, hydraulic type, torque converter, or other continuously variable transmission. You can also use a machine.

[0028]

As explained in detail above, according to the present invention, in a friction continuously variable transmission having a continuously variable transmission mechanism and a differential gear mechanism, an input shaft and an output shaft having the same center axis are connected. A differential gear mechanism is provided on the outer periphery of the input shaft to divide the rotational force transmitted to the input shaft, and
Since a continuously variable transmission mechanism connected to the differential gear mechanism is provided on the outer circumference of the output shaft, when rotational force is transmitted to the input shaft of the friction continuously variable transmission, one side of the rotational force is transmitted through the differential gear mechanism. The configuration is such that the rotational force is transmitted to the output shaft, and the other side of the rotational force is transmitted to the output shaft via a differential gear mechanism and a continuously variable transmission mechanism, respectively, so that the rotational force is divided.

[0029] Therefore, a large torque can be transmitted with a small capacity continuously variable transmission. Furthermore, if the transmission capacity of the continuously variable transmission is the same, the transmission can be made smaller. Furthermore,
The input rotational speed to the continuously variable transmission mechanism is reduced by the differential gear mechanism at the front stage, thereby making it possible to rotate the input shaft at high speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a stop position of a continuously variable friction transmission.

FIG. 2 is a schematic diagram of a continuously variable friction transmission.

[Explanation of symbols]

2 Friction continuously variable transmission 4 Differential gear mechanism 6 Continuously variable transmission mechanism 8 Input shaft 10 Output shaft 14 Case 16 Sun gear 18 Planetary gear 18a Carrier 20 Internal gear 22 Small diameter transmission wheel 28 Conical trochanter 30 Cone retainer 32 Speed change ring 34 Large diameter transmission wheel 36a Thrust cam 36b Thrust cam 38 Thrust ball

Claims (1)

[Claims] Claim 1: A conical surface that is inscribed in and frictionally engaged with a speed change ring that is kept in a non-rotating state, an annular transmission surface that is frictionally engaged with a small diameter transmission wheel on an input shaft, and a large diameter transmission wheel. A plurality of conical rotors with flat transmission surfaces that are frictionally engaged with the wheel are installed on the transmission system, and the rotation of the large transmission wheel is transmitted to the output shaft via a cam-type pressure generating device. is,
In a type in which the speed change is performed by moving the speed change ring in the axial direction to change the effective radius of the conical rotor relative to the speed change ring, it is rotated by integrating the sun gear on the input shaft and the small diameter transmission wheel. A differential gear device includes an internal gear, a planetary gear interposed between the internal gear and the sun gear, and a carrier for the planetary gear, and an output signal is output to the carrier of the differential gear device. A continuously variable friction transmission characterized by engaging one end of a shaft.